Vehicles are manufactured with an array of electronic hardware that regulates vehicle function. The electronic hardware includes sensors, electronic control units (ECUs; also called vehicle systems modules), vehicle telematics units, as well as other devices that communicate with each other over a communications bus. The devices included with the electronic hardware carry out not only intra-vehicle communications but can also accept instructions from outside of the vehicle. For instance, vehicles commonly include an on-board diagnostics (OBD) input that can be used to provide instructions to or receive data from the electronic hardware. Vehicles also can remotely receive instructions and communicate data using wireless communications techniques implemented by the vehicle telematics unit and other ECUs so equipped. By maintaining portals providing access to the electronic hardware, it is possible that the portals can be used for malicious or other unauthorized access to the electronic hardware. But the vehicle can detect input to the electronic hardware that is unauthorized. However, once the vehicle detects the presence of harmful input determining how to ameliorate the harmful input can be challenging.